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23 Cards in this Set
- Front
- Back
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What type of photoreceptor cells are most prevalent at the macula and fovea? Describe the vasculature of this area.
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*cones
*it is avascular |
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What type of photoreceptor cell is found in the optic disk?
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The optic disk has no photoreceptors - it is the site of the blind spot.
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How does papilledema appear on fundascopic exam? What condition does this signal?
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*the optic disk bulges and its margins becoem less distinct
*increased intracranial pressure |
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Which retinal ganglion cells cross at he optic chiasm? Which synapse at the ipsilateral LGN?
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*nasal retinal ganglion cells cross at the chiasm
*temporal RGC synapse at the ipsilateral LGN |
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Describe the sympathetic pathway for control of pupillary diameter.
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1.Retina
2.MFB 3.T1,T2 intermediolateral horn 4.Superior cervical ganglion 5.Dilator muscles |
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Describe the pathway for parasympathetic control of pupillary size.
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1.Retina
2.Pretectal area 3.Edinger-Westphal nucleus 4.CN III 5.Ciliary ganglion 6.Constrictor muscles |
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Which pretectal area (right or left) does the right retina send fibers to? The left retina?
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Each eye sends fibers to both the ipsilateral and contralateral pretectal areas.
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What part of the visual field is perceived by the left nasal retina? By the left temporal retina?
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*left nasal retina: left temporal field
*left temporal retina: right nasal field |
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Do lesions that occur behind the optic chiasm produce ipsilateral or contralateral deficits? Or deficits on both sides?
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Contralateral.
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Which portion of the optic radiations carry fibers that synapse at the lingula?
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Those fibers found in Meyer's Loop - the most lateral portion of the optic radiations.
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What structure connects the LGN and the superior colliculus?
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The brachium
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Where might a lesion be that produces upper right quadrantanopsia?
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In the left Meyer's loop or left lingula.
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What deficits would be produced by a lesion in the cuneus?
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Contralateral lower field deficits.
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Describe the deficit caused with a lesion to the fibers connecting the left retina to the right and left pretectal areas.
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*no direct or consensual constriction when left eye is exposed to light
*consensual constriction when light is shown in right eye |
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What are the 4 symptoms of Horner's Syndrome? What causes this syndrome?
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1.Miosis, ptosis, anhidrosis, flushing
2.Damage to sympathetic innervation of head and neck |
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Describe the primary sign of Argyle-Robertson syndrome.
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The pupil is able to constrict during accomodation, but does not exhibit light reflexes.
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What area in the brain controls horizontal eye movements? Does this area receive fibers from the ipsilateral or conttralateral frontal eye field.
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*paramedian pontine reticular formation (PPRF)
*receives fibers from the contralateral frontal eye field |
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Which cranial nerve nuclei must the PPRF coordinate to produce cooperative bilateral horizontal eye movements?
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*CN III
*CN VI |
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Visuospatial integration takes place in the MT area in the parietal cortex. Through what structure does information pass to get from the retina to the MT area?
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Superior colliculus (and pulvinar)
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Visuospatial integration takes place in the MT area in the parietal cortex. Through what structure does information pass to get from the retina to the MT area?
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Superior colliculus (and pulvinar)
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The LGN is a part of what larger brain cerebral structure?
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Thalamus.
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What is a scotoma?
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A defect in the perceived visual field
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Where are the cell bodies of neurons whose axons run in the left optic tract?
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In the left temporal retina and right nasal retina (ganglion layers).
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